Are we humans simply remodelled apes? Chimps with a tweak? Is the difference between our genomes so minuscule it justifies the argument that our cognition and behaviour must also differ from chimps by barely a whisker? If “chimps are us” should we grant them human rights? Or is this one of the biggest fallacies in the study of evolution? NOT A CHIMP argues that these similarities have been grossly over-exaggerated - we should keep chimps at arm’s length. Are humans cognitively unique after all?

NOT A CHIMP

Click on the cover to link to OUP's e-catalogue then turn to the biology section.

Interview Podcast with George Miller

Click on the pic to link to the NOT A CHIMP podcast on Blackwell's Website

Preface to "Not A Chimp: The Hunt For The Genes That Make Us Human"

In many ways, this book is born out of frustration for a professional career in popular science television where ideas about comparative primate cognition, and the similarities and differences between us and our primate relatives, have continually circled me but constantly evaded my grasp in terms of the opportunity to transform them into science documentary. On the plus side, keeping a watching brief for over a quarter of a century on subjects like comparative animal cognition and evolution allows you to watch a great deal of water flow under the bridge. Fashions come and fashions go - specifically, perspectives on the similarity - or otherwise - of human and ape minds.

I remember the first Horizon science documentary about the chimpanzee Washoe, the great ape communicator, using American Sign Language to bridge the species barrier. And, later, Kanzi the bonobo jabbing his lexicon. These were the apes, as Sue Savage-Rumbaugh has put it, that were "on the brink of the human mind".

I remember when the pre-print of Machiavellian Intelligence, by Andrew Whiten and Dick Byrne, plopped onto the doormat of the BBC Antenna science series office in 1988. Suddenly primatology had become a great deal more exciting. Could primates, and especially higher primates like chimpanzees, really be as full of guile, as dastardly, as cunning, and as manipulative as the eponymous Florentine politician? Could they really reach deep into the minds of other individuals to see what they believed and what they wanted, and turn that information into deception?

I remember discussing primate cognition with a young Danny Povinelli, as we sat finger-feeding ourselves shrimp gumbo and new potatoes out of plastic Tupperware containers in a Lafayette restaurant surrounded by an alligator-infested moat, before returning to his kingdom - the New Iberia Research Centre - where the University of Louisiana had lured him back to his native deep South by turning a chimpanzee breeding centre for medical laboratory fodder into a primate cognition laboratory with one of the largest groups of captive chimpanzees in the country. He looked like a kid who had just been thrown the keys to the tuck shop.

In those days Povinelli shared the zeitgeist - spread by Whiten's and Byrne's work, and started by Nick Humphrey and Alison Jolly before them - that, since the most exacting and potentially treacherous environment faced by chimpanzees and other primates was not physical, but the social environment of their peers, they had evolved a form of social cognition very much like our own, in order to deal with it. This was further elaborated into a full-blown "social brain" hypothesis by Robin Dunbar, who related brain neocortex size to social group size throughout the primates and up to man. Povinelli's early work reflects this optimism for the mental life of apes, but both ape-language and ape-cognition research was subjected to a cold douche of searching criticism during the 1990s, and misgivings set in regarding the effectiveness of the experiments that had been constructed to guage ape cognition. Now the worm has turned again, with a number of research groups emerging with bolder and bolder claims for the Machiavellian machinations of primate minds, only to be powerfully countered by the curmudgeonly skepticism, chiefly by Povinelli, that these researchers are merely projecting their mental life onto that of their subjects; that, rather in the frustrating manner of Zeno's arrow that could never quite reach its target because it continually halved its distance to it, no experiment constructed thus far can actually get inside the mind of a chimp and show us exactly what it does and doesn't know, or how much, about the minds of others or the way the physical world works. One influential part of the world of comparative animal cognition talks of a continuum between ape and human minds and shrinks the cognitive distance between us and chimps to almost negligible proportions, while another returns us to the unfashionable idea that human cognition is unique, among the primates, after all.

When I began writing this book the working title was "The 1.6% that makes us human". My aim had always been to scrutinize the impression put about in the popular science media that humans and chimps differ by a mere 1.6% in our genetic code - or even less - and that it therefore makes complete sense that this minuscule genetic difference translates into equally small differences in cognition and behaviour between apes and man. However, contemporary genome science and technology, over the last few years, have dramatically advanced the power and resolution with which scientists can investigate genomes, eclipsing the earlier days of genomic investigation that gave rise to the "1.6% mantra".

As with comparative cognitive studies, conclusions on chimp-human similarity and difference in genome research depend crucially on perspective. To look at the complete set of human chromosomes, side by side with chimpanzee chromosomes, at the level of resolution of a powerful light microscope, for instance, is to be overwhelmed by the similarity between them. Overwhelmed with a sense of how close our kinship is with the other great apes. True, our chromosome 2 is a combination of two chimp chromosomes - giving humans a complement of 23 chromosome pairs to 24 in chimps, gorillas and orang-utans - but even here you can see exactly where the two chimp chromosomes have fused to produce one. The banding patterns you visualize by staining the chromosomes match up with astonishing similarity - and that banding similarity extends to many of the other chromosomes in the two genomes. However, look at a recent map of the chromosomes of chimps and humans, aligned side by side, produced by researchers who have mapped all inversions - end-on-end flips of large chunks of DNA - and the chromosomes are all but blotted out by a blizzard of red lines denoting inverted sequence. Now you become overwhelmed by how much structural change has occurred between the two genomes in just 6 million years. True, not all inversions result in changes in the working of genes - but many do - and inversions might even have been responsible for the initial divergence of chimp ancestor from human ancestor.

The extent to which you estimate the difference between chimp and human genomes depends entirely on where you look and how deeply. Modern genomics technology has led us deep into the mine that is the genome and has uncovered an extraordinary range of genetic mechanisms, many of which have one thing in common. They operate to promote variability - they amplify differences between individuals in one species. We now know, for instance, that each human is less genetically identical to anyone else than we thought only three years ago. When we compare human genomes to chimpanzee genomes these mechanisms magnify genetic distance still further. I have tried, in this book, to follow in the footsteps of these genome scientists as they dig deeper and deeper into the "Aladdin's Cave" of the genome. At times the going gets difficult. Scientists, like any explorers, are prone to taking wrong turnings, getting trapped in thickets, and covering hard ground, before breaking through into new insights. I hope that those of you who recoil from genetics with all the visceral horror with which many regard the sport of pot-holing will steel yourselves and follow me as far as I have dared to go into Aladdin's Cave. For only then will you see the riches within and begin to appreciate, as I have, just how limited popular accounts of human-chimpanzee genetic difference really are. Let me try and persuade you that this is a journey, if a little arduous at times, that is well worth taking.

There are a number of scientists around the world who have the breadth and the vision to have begun the task of rolling genetics, comparative animal cognition, and neuroscience into a comprehensive new approach to the study of human nature and this is part, at least, of their story. They strive to describe the nature of humans in terms of the extent to which we are genuinely different to chimpanzees and the other great apes. Somehow, over 6 million years, we humans evolved from something that probably resembled a chimpanzee (though we cannot yet be entirely sure) and the answer to our evolution has to lie in a growing number of structural changes in our genome, versus that of the chimpanzee, that have led to the evolution of a large number of genes that have, effectively, re-designed our brains and led to our advanced and peculiar human cognition.

If you don't believe me, hand this book to your nearest friendly chimpanzee and see what he makes of it!

Friday, 4 September 2009

NOT A CHIMP was released in the US and Canada this week and the influential Huffington Post is the first to review it. Although neuroscientist Dan Agin disagrees with the book's premise he concludes:

Into this debate about similarities and differences between chimpanzees and humans now arrives a new book by Jeremy Taylor, a UK BBC science journalist and film producer. It's an interesting and readable book, particularly since Taylor takes a strong position in the debate. His focus is on differences, but his argument is biological rather than religious or philosophical. He makes three main points:

1) We have been evolving much faster than the chimpanzees. The rate of evolution in the human genome has apparently increased since we and the chimps split from a common ancestor. At least 7 percent of human genes have evidently changed within the past 50,000 years.

2) We humans have apparently domesticated ourselves in exactly the same way that we have cultivated farm animals, dogs, and crop plants from their wild progenitors.

3) Taylor believes that misguided scientists have suggested a closer genetic relationship between humans and chimpanzees in order to build sympathy for an endangered species.

These are strong views. Many people (including myself) may be opposed to Taylor's conclusions, but this is a provocative book that should be read by anyone interested in the debate about similarities and differences between humans and chimpanzees.

Thursday, 3 September 2009

Really nice essay on the essential differences between humans and the rest of the higher primates from an old friend of mine, the anthropologist Sarah Blaffer Hrdy - based on her most recent book MOTHERS AND OTHERS. Hrdy argues that the crucial wide differences between the species come in the social realm and involve huge increases in the human propensities for mutual tolerance, social communication and intention-reading.

In the chapter on domestication in NOT A CHIMP I present evidence showing that dogs are much better than chimps and wolves (from whom dogs are supposed to have evolved) at following human pointing gestures as to the location of food. I also show that tamed Arctic foxes are as good as dogs on these sorts of tasks. So, have dogs (tamed wolves) and tamed foxes evolved some aspects of social intelligence that is peculiar to the domestication process, and, if so, what? Adam Miklosi and colleagues from Eotvos University in Hungary have added a little complexity to the story. They show that socialised young wolves are capable of following simple human pointing cues after all - though there is delayed emergence of these social skills compared with dogs. The young wolves had been human-reared and bottle fed since pups. The experimenter drops food into bowls in a hidden way by turning away from the subject. On turning back and placing bowls to her left and right she signals with a finger point which bowl has the food - it is not possible, because of the equipment, for the animal to use its own sense of smell. The wolves equaled the performance of dogs on the simpler task where the pointing finger is less than 50 cm. from the bowl, but slightly worse which the pointing gesture was more distal - in excess of 50 cm. Also, the wolves took longer to attend to the experimenter - they took longer to establish eye contact, stop wrestling with their handlers and stop attempting to bite the experimenter! The researchers conclude that, while the difference between human reared wolves and dogs on these tasks is not as marked as previously thought, the delay in the wolves suggests they do not react to the same extent to extensive socialisation as the dogs which "are able to control agonistic behaviours". In other words the dogs are still slightly ahead because their natural tendency for fight or flight has been bred out of them over thousands of years of co-existence with humans. They therefore find it easier to fix attention on humans with less fear and aggression.

A research team from the Goualougo Triangle Ape Project, headed by Crickette Sanz, have provided evidence that chimp tool-making and use to dip for several species of ant is more sophisticated than previously thought. Chimps generally use a long twig to actually dip for the ants - the ants climb up the twig and are thus transported to the chimp's mouth. But, where they have to break into the nest, they use a different twig tool to penetrate the nest and make an opening. Specifically, the number of tools used per site was an average of 3.37 and just over one third of recovered tool sets contained a mixture of nest perforating and ant dipping tools. There was evidence that the nest perforation tools were selectively used by the chimps to open the nests of the more aggressive epigaeic ants - where wholesale smashing of the nests would release swarms of highly aggressive biting ants driven with retaliatory intent. Using a perforation tool is clearly a more delicate technique to control ant emergence and collateral damage to self. However this report is tarnished, in my eyes, by a couple of highly anthropomorphic observations attributed to the researchers. The first is that by delicately perforating the nests, rather than smashing them, the chimps are practicing "sustainable harvesting". This begs the assumption that chimps have a deep forward planning knowledge which allows them to manage resources long into the future - which is not sustained by the mainstream of primatological research. The authors also assert that the chimps practice recycling by re-using tools that have been left by other individuals. I hope that, in the original paper, they word it to say that the effect is to recycle - rather than the intent is to recycle!

Wednesday, 2 September 2009

How long ago did early humans begin using fire to make tools? Previous reports suggest it was a relatively new invention - dating back a mere 30,000 years or so. However, a team from the University of Capetown have re-calibrated the event. They discovered that it was impossible for them to re-create the stone tools found at the Pinnacle Point caves in South Africa unless they used 20 to 40 kilograms of hardwood and heated the silcrete from which they were fashioned to more than 300 degrees C over 30 hours. Tests reveal that original heat-treated tools are at least 70,000 years old and may even be as old as 164,000 years. So, humans had a much more sophisticated fire-assisted technology, earlier than previously thought. My interest lies in Richard Wrangham's theory for cooking being the explosive force behind earlier human brain expansion. His theory is be-deviled, so far, by lack of evidence for hearths going back 2 million + years. Evidence suggesting a far more sophisticated use of fire than that for cooking, dating back to the earliest origins of Homo sapiens in Africa, pushes the boundary of fire technology deeper into the past and may help make Wrangham's theory more tenable.

Whatever the rampant growth of human neo-cortex does it does not always make us more rational than other animals. Keith Jenson, Josep Call and Mike Tomasello, from the Max Planck Institute in Leipzig, compared humans and chimps on species-suitable versions of the ultimatum game in which one individual is expected to maximize assets he is given by being miserly toward the second partner. The assumption is that humans will be rationally self-interested - indeed the idea underpins most of economics. However, humans play irrationally because they factor in notions of fairness and cooperation such that they give more than they "should". This clearly reflects the intense evolutionary development of our "social brain". Chimps, however, are ruthlessly rational - giving the tiniest amounts away. The other partner in the game seems always happy with whatever crumbs he receives.

As this fascinating Nature piece explains, in 2006 David Reich and colleagues from the Broad Institute in Cambridge, MA compared the genomes of humans, chimps and three other primates and concluded that the divergence of human and chimp ancestors could not have been a clean break but was a messy business involving more than 4 million years and two splits - an initial divide followed by a long period of interbreeding, and then a final separation in which only the young X chromosome was retained. It was the apparent youth of the X chromosome, compared with all the non-sex chromosomes, that demanded this explanation.

Now, however, Soojin Yi and colleagues, from the Georgia Institute of Technology, have challenged an interpretation which has always proved difficult to swallow for the genomics community at large. No need to involve complex speciation, they argue, because the data can be explained by a well-known difference in female promiscuity ranging from high in chimps, through intermediate in humans, to low in gorilla. High female promiscuity leads to relatively large testes and sperm counts. This means, says Yi, more rounds of cell division making all that sperm - in chimps - which increases the mutation load on chimp sperm - more mutations in males than females. This male-biased mutation rate will favour non-sex chromosomes, the mutation rate in the X will be lower, and, since the molecular clock of evolution is calculated in mutation over time, the X will therefore appear to be younger - when, in fact, it is not. Reich challenges back but, at least, as Nick Barton suggests, we now have an exciting alternative explanation for the chimp-human divergence which can be tested. Watch this space!

Here is an extremely novel approach to explaining the origin of genes unique to the human line. David Knowles and Aoife McLysaght, from the Smurfit Institute of Genetics in Dublin, have identified 3 genes that are present in the human genome but not present in the chimp. They appear to have been made active in humans from inactive sequences of DNA in chimps and a range of other primates. The researchers have determined that these genes are active in humans because they do produce protein but they have no information yet on what, exactly, these genes do. They do point out, however, that they have only filtered about 20% of the human genome for human-chimp comparison and that their research may yet realize some 18+ genes that have arisen from non-coding DNA in human evolution.

In the chapter on domestication in NOT A CHIMP I favour a version of dog evolution which posits that humans did not actively go out to tame wild wolves but that, if anything, wolves are too large to have been likely dog progenitors and that at least the early stages in the evolution of dogs involved a loose form of commensalism in which a smaller wolf-like species or other wild canid tamed itself by selecting for the ability to tolerate human proximity while foraging in rubbish dumps on the periphery of early human settlements. This still leaves open the question of likely dates during which this process might have occurred. Now Peter Savolainen and a number of Chinese colleagues have examined mitochondrial DNA from wolves and extant dogs and decided that the cradle for domestication of dogs was in China, probably just south of the Yangtse river, about 16,000 years ago. Humans and dogs subsequently ranged widely over Asia and dogs thereby wound up in Natufian settlements in present-day Israel by about 11,000 years ago. 16,000 years ago was the earliest time for a change from hunter-gatherer to sedentary agriculturalists in present-day China, and the beginning of rice cultivation. These researchers believe the progenitor was the smallish Chinese wolf, and, while nodding in the direction of the commensalism theory, they clearly favour a more active role for humans in selection among wolf females for tamable offspring. This runs counter to a large body of information on wolves that suggests they are, effectively, un-tamable. Interestingly they present a completely new angle on the motivation for this supposed domestication of wolves by suggesting they were used as a food resource! The Chinese are reputedly fond of dog-meat to this day but I think this is a shaggy dog domestication story!

Welcome to NOT A CHIMP!

It's estimated that there are 225 chimpanzees kept as pets in American homes - often with catastrophic, unforeseen results. In February, 2009, Travis, a 14 year old chimp, who lived with a Stamford, CT woman, attacked and mauled her best friend, went on the rampage, cornered police in their patrol car and was eventually shot dead. Welcome to the bizarre world of human-chimp relationships! So, are chimps so like us they can slip comfortably into our domestic bliss, or are they wild animals and should be respected as such? This blog and the book, "Not A Chimp" to which it is dedicated, fillets the latest research from genetics, cognition and neuroscience to inform this debate and help you decide. I'll be posting commentary and links to a variety of hot-off-the-press articles and scientific papers published since the book was written and links to a variety of web-sites you might like to visit to explore human-chimpanzee world a little further!

"NOT A CHIMP" GOES INTO PAPERBACK!

NOT A CHIMP was published in the UK in hard-back in June 2009.Later, in September 2009, it was also launched in the USA and Canada. Now, today, 25th May, 2010 sees its publication in the UK in paperback - with the usual world-wide distribution soon to follow.

Meet The Author

Click on me to link to a 3 minute video about the book.

About Me

I have spent most of my professional life inside the science documentary television industry, with evolutionary biology a subject I have visited many times. Until 1992 I was a senior producer and director for BBC Television, where I contributed many films to the BBC’s long-running flagship science series ‘Horizon’ (including two landmark programmes presented by Richard Dawkins, “Nice Guys Finish First” and “The Blind Watchmaker”). My first book, “Not a Chimp” ('A provocative book that should be read by anyone interested in the debate about similarities and differences between humans and chimpanzees', Dan Agin, Huffington Post) was published by Oxford University Press in 2009. My second book, “Body By Darwin”, to which this blog is dedicated, will be published by University of Chicago Press in October, 2015.